# dlacon(3) [centos man page]

dlacon.f(3) LAPACK dlacon.f(3)NAME

dlacon.f-SYNOPSIS

Functions/Subroutines subroutine dlacon (N, V, X, ISGN, EST, KASE) DLACON estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products.Function/Subroutine Documentation subroutine dlacon (integerN, double precision, dimension( * )V, double precision, dimension( * )X, integer, dimension( * )ISGN, double precisionEST, integerKASE) DLACON estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products. Purpose: DLACON estimates the 1-norm of a square, real matrix A. Reverse communication is used for evaluating matrix-vector products. Parameters: N N is INTEGER The order of the matrix. N >= 1. V V is DOUBLE PRECISION array, dimension (N) On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned). X X is DOUBLE PRECISION array, dimension (N) On an intermediate return, X should be overwritten by A * X, if KASE=1, A**T * X, if KASE=2, and DLACON must be re-called with all the other parameters unchanged. ISGN ISGN is INTEGER array, dimension (N) EST EST is DOUBLE PRECISION On entry with KASE = 1 or 2 and JUMP = 3, EST should be unchanged from the previous call to DLACON. On exit, EST is an estimate (a lower bound) for norm(A). KASE KASE is INTEGER On the initial call to DLACON, KASE should be 0. On an intermediate return, KASE will be 1 or 2, indicating whether X should be overwritten by A * X or A**T * X. On the final return from DLACON, KASE will again be 0. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Contributors: Nick Higham, University of Manchester. Originally named SONEST, dated March 16, 1988. References: N.J. Higham, 'FORTRAN codes for estimating the one-norm of a real or complex matrix, with applications to condition estimation', ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988. Definition at line 116 of file dlacon.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 dlacon.f(3)

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dlacon.f(3) LAPACK dlacon.f(3)NAME

dlacon.f-SYNOPSIS

Functions/Subroutines subroutine dlacon (N, V, X, ISGN, EST, KASE) DLACONFunction/Subroutine Documentation subroutine dlacon (integerN, double precision, dimension( * )V, double precision, dimension( * )X, integer, dimension( * )ISGN, double precisionEST, integerKASE) DLACON Purpose: DLACON estimates the 1-norm of a square, real matrix A. Reverse communication is used for evaluating matrix-vector products. Parameters: N N is INTEGER The order of the matrix. N >= 1. V V is DOUBLE PRECISION array, dimension (N) On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned). X X is DOUBLE PRECISION array, dimension (N) On an intermediate return, X should be overwritten by A * X, if KASE=1, A**T * X, if KASE=2, and DLACON must be re-called with all the other parameters unchanged. ISGN ISGN is INTEGER array, dimension (N) EST EST is DOUBLE PRECISION On entry with KASE = 1 or 2 and JUMP = 3, EST should be unchanged from the previous call to DLACON. On exit, EST is an estimate (a lower bound) for norm(A). KASE KASE is INTEGER On the initial call to DLACON, KASE should be 0. On an intermediate return, KASE will be 1 or 2, indicating whether X should be overwritten by A * X or A**T * X. On the final return from DLACON, KASE will again be 0. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: November 2011 Contributors: Nick Higham, University of Manchester. Originally named SONEST, dated March 16, 1988. References: N.J. Higham, 'FORTRAN codes for estimating the one-norm of a real or complex matrix, with applications to condition estimation', ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988. Definition at line 116 of file dlacon.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.1Sun May 26 2013 dlacon.f(3)